Support for block device NVMEM providers

Documentation/devicetree/bindings/mmc/mmc-card.yaml

@@ -40,6 +40,9 @@ patternProperties:
         contains:
           const: fixed-partitions
 
+      nvmem-layout:
+        $ref: /schemas/nvmem/layouts/nvmem-layout.yaml
+
 required:
   - compatible
   - reg
@@ -86,6 +89,32 @@ examples:
                     read-only;
                 };
             };
+
+            partitions-boot2 {
+                compatible = "fixed-partitions";
+
+                #address-cells = <1>;
+                #size-cells = <1>;
+
+                nvmem-layout {
+                    compatible = "fixed-layout";
+
+                    #address-cells = <1>;
+                    #size-cells = <1>;
+
+                    mac-addr@4400 {
+                        compatible = "mac-base";
+                        reg = <0x4400 0x6>;
+                        #nvmem-cell-cells = <1>;
+                    };
+
+                    bd-addr@5400 {
+                        compatible = "mac-base";
+                        reg = <0x5400 0x6>;
+                        #nvmem-cell-cells = <1>;
+                    };
+                };
+            };
         };
     };
 

Documentation/devicetree/bindings/net/bluetooth/qcom,bluetooth-common.yaml

@@ -22,4 +22,13 @@ properties:
     description:
       boot firmware is incorrectly passing the address in big-endian order
 
+  nvmem-cells:
+    maxItems: 1
+    description:
+      Nvmem data cell that contains a 6 byte BD address with the most
+      significant byte first (big-endian).
+
+  nvmem-cell-names:
+    const: local-bd-address
+
 additionalProperties: true

Documentation/devicetree/bindings/net/wireless/qcom,ath10k.yaml

@@ -92,6 +92,22 @@ properties:
 
   ieee80211-freq-limit: true
 
+  nvmem-cells:
+    minItems: 1
+    maxItems: 3
+    description:
+      References to nvmem cells for MAC address and/or calibration data.
+      Supported cell names are mac-address, calibration, and pre-calibration.
+
+  nvmem-cell-names:
+    minItems: 1
+    maxItems: 3
+    items:
+      enum:
+        - mac-address
+        - calibration
+        - pre-calibration
+
   qcom,calibration-data:
     $ref: /schemas/types.yaml#/definitions/uint8-array
     description:

arch/arm64/boot/dts/qcom/qrb2210-arduino-imola.dts

@@ -409,7 +409,40 @@
 	no-sdio;
 	no-sd;
 
+	#address-cells = <1>;
+	#size-cells = <0>;
+
 	status = "okay";
+
+	card@0 {
+		compatible = "mmc-card";
+		reg = <0>;
+
+		partitions-boot1 {
+			compatible = "fixed-partitions";
+
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			nvmem-layout {
+				compatible = "fixed-layout";
+				#address-cells = <1>;
+				#size-cells = <1>;
+
+				wifi_mac_addr: mac-addr@4400 {
+					compatible = "mac-base";
+					reg = <0x4400 0x6>;
+					#nvmem-cell-cells = <1>;
+				};
+
+				bd_addr: bd-addr@5400 {
+					compatible = "mac-base";
+					reg = <0x5400 0x6>;
+					#nvmem-cell-cells = <1>;
+				};
+			};
+		};
+	};
 };
 
 &spi5 {
@@ -512,6 +545,9 @@
 		vddch0-supply = <&pm4125_l22>;
 		enable-gpios = <&tlmm 87 GPIO_ACTIVE_HIGH>;
 		max-speed = <3000000>;
+
+		nvmem-cells = <&bd_addr 0>;
+		nvmem-cell-names = "local-bd-address";
 	};
 };
 
@@ -557,6 +593,9 @@
 	qcom,ath10k-calibration-variant = "ArduinoImola";
 	firmware-name = "qcm2290";
 
+	nvmem-cells = <&wifi_mac_addr 0>;
+	nvmem-cell-names = "mac-address";
+
 	status = "okay";
 };
 

block/Kconfig

@@ -209,6 +209,15 @@ config BLK_INLINE_ENCRYPTION_FALLBACK
 	  by falling back to the kernel crypto API when inline
 	  encryption hardware is not present.
 
+config BLK_NVMEM
+	bool "Block device NVMEM provider"
+	depends on OF
+	depends on NVMEM
+	help
+	  Allow block devices (or partitions) to act as NVMEM providers,
+	  typically used with eMMC to store MAC addresses or Wi-Fi
+	  calibration data on embedded devices.
+
 source "block/partitions/Kconfig"
 
 config BLK_PM

block/Makefile

@@ -36,3 +36,4 @@ obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= blk-crypto.o blk-crypto-profile.o \
 					   blk-crypto-sysfs.o
 obj-$(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK)	+= blk-crypto-fallback.o
 obj-$(CONFIG_BLOCK_HOLDER_DEPRECATED)	+= holder.o
+obj-$(CONFIG_BLK_NVMEM)                += blk-nvmem.o

block/blk-nvmem.c

@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * block device NVMEM provider
+ *
+ * Copyright (c) 2024 Daniel Golle <daniel@makrotopia.org>
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ *
+ * Useful on devices using a partition on an eMMC for MAC addresses or
+ * Wi-Fi calibration EEPROM data.
+ */
+
+#include <linux/file.h>
+#include <linux/nvmem-provider.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/pagemap.h>
+#include <linux/property.h>
+
+#include "blk.h"
+
+static int blk_nvmem_reg_read(void *priv, unsigned int from, void *val, size_t bytes)
+{
+	blk_mode_t mode = BLK_OPEN_READ | BLK_OPEN_RESTRICT_WRITES;
+	dev_t devt = (dev_t)(uintptr_t)priv;
+	size_t bytes_left = bytes;
+	loff_t pos = from;
+	int ret = 0;
+
+	struct file *bdev_file __free(fput) = bdev_file_open_by_dev(devt, mode, priv, NULL);
+	if (IS_ERR(bdev_file))
+		return PTR_ERR(bdev_file);
+
+	while (bytes_left) {
+		pgoff_t f_index = pos >> PAGE_SHIFT;
+		struct folio *folio;
+		size_t folio_off;
+		size_t to_read;
+
+		folio = read_mapping_folio(bdev_file->f_mapping, f_index, NULL);
+		if (IS_ERR(folio)) {
+			ret = PTR_ERR(folio);
+			break;
+		}
+
+		folio_off = offset_in_folio(folio, pos);
+		to_read = min(bytes_left, folio_size(folio) - folio_off);
+		memcpy_from_folio(val, folio, folio_off, to_read);
+		pos += to_read;
+		bytes_left -= to_read;
+		val += to_read;
+		folio_put(folio);
+	}
+
+	return ret;
+}
+
+void blk_nvmem_add(struct block_device *bdev)
+{
+	struct device *dev = &bdev->bd_device;
+	struct nvmem_config config = {};
+
+	/* skip devices which do not have a device tree node */
+	if (!dev_of_node(dev))
+		return;
+
+	/* skip devices without an nvmem layout defined */
+	struct device_node *child __free(device_node) =
+		of_get_child_by_name(dev_of_node(dev), "nvmem-layout");
+	if (!child)
+		return;
+
+	/*
+	 * skip block device too large to be represented as NVMEM devices,
+	 * the NVMEM reg_read callback uses an unsigned int offset
+	 */
+	if (bdev_nr_bytes(bdev) > UINT_MAX) {
+		dev_warn(dev, "block device too large to be an NVMEM provider\n");
+		return;
+	}
+
+	config.id = NVMEM_DEVID_NONE;
+	config.dev = dev;
+	config.name = dev_name(dev);
+	config.owner = THIS_MODULE;
+	config.priv = (void *)(uintptr_t)dev->devt;
+	config.reg_read = blk_nvmem_reg_read;
+	config.size = bdev_nr_bytes(bdev);
+	config.word_size = 1;
+	config.stride = 1;
+	config.read_only = true;
+	config.root_only = true;
+	config.ignore_wp = true;
+	config.of_node = to_of_node(dev->fwnode);
+
+	bdev->bd_nvmem = nvmem_register(&config);
+	if (IS_ERR(bdev->bd_nvmem)) {
+		dev_err_probe(dev, PTR_ERR(bdev->bd_nvmem),
+			      "Failed to register NVMEM device\n");
+		bdev->bd_nvmem = NULL;
+	}
+}
+
+void blk_nvmem_del(struct block_device *bdev)
+{
+	if (bdev->bd_nvmem)
+		nvmem_unregister(bdev->bd_nvmem);
+
+	bdev->bd_nvmem = NULL;
+}

block/blk.h

@@ -778,4 +778,12 @@ static inline void blk_debugfs_unlock(struct request_queue *q,
 	memalloc_noio_restore(memflags);
 }
 
+#ifdef CONFIG_BLK_NVMEM
+void blk_nvmem_add(struct block_device *bdev);
+void blk_nvmem_del(struct block_device *bdev);
+#else
+static inline void blk_nvmem_add(struct block_device *bdev) {}
+static inline void blk_nvmem_del(struct block_device *bdev) {}
+#endif
+
 #endif /* BLK_INTERNAL_H */

block/genhd.c

@@ -421,6 +421,8 @@ static void add_disk_final(struct gendisk *disk)
 		 */
 		dev_set_uevent_suppress(ddev, 0);
 		disk_uevent(disk, KOBJ_ADD);
+
+		blk_nvmem_add(disk->part0);
 	}
 
 	blk_apply_bdi_limits(disk->bdi, &disk->queue->limits);
@@ -704,6 +706,8 @@ static void __del_gendisk(struct gendisk *disk)
 
 	disk_del_events(disk);
 
+	blk_nvmem_del(disk->part0);
+
 	/*
 	 * Prevent new openers by unlinked the bdev inode.
 	 */

block/partitions/of.c

@@ -15,6 +15,10 @@ static int validate_of_partition(struct device_node *np, int slot)
 	int a_cells = of_n_addr_cells(np);
 	int s_cells = of_n_size_cells(np);
 
+	/* Skip nodes without a reg property (e.g. nvmem-layout) */
+	if (!reg)
+		return 1;
+
 	/* Make sure reg len match the expected addr and size cells */
 	if (len / sizeof(*reg) != a_cells + s_cells)
 		return -EINVAL;
@@ -80,14 +84,15 @@ int of_partition(struct parsed_partitions *state)
 	slot = 1;
 	/* Validate parition offset and size */
 	for_each_child_of_node(partitions_np, np) {
-		if (validate_of_partition(np, slot)) {
+		int err = validate_of_partition(np, slot);
+
+		if (err < 0) {
 			of_node_put(np);
 			of_node_put(partitions_np);
-
 			return -1;
 		}
-
-		slot++;
+		if (!err)
+			slot++;
 	}
 
 	slot = 1;
@@ -97,9 +102,10 @@ int of_partition(struct parsed_partitions *state)
 			break;
 		}
 
-		add_of_partition(state, slot, np);
-
-		slot++;
+		if (of_property_present(np, "reg")) {
+			add_of_partition(state, slot, np);
+			slot++;
+		}
 	}
 
 	seq_buf_puts(&state->pp_buf, "\n");

drivers/bluetooth/btqca.c

@@ -721,8 +721,11 @@ static int qca_check_bdaddr(struct hci_dev *hdev, const struct qca_fw_config *co
 	}
 
 	bda = (struct hci_rp_read_bd_addr *)skb->data;
-	if (!bacmp(&bda->bdaddr, &config->bdaddr))
+	if (!bacmp(&bda->bdaddr, &config->bdaddr)) {
 		hci_set_quirk(hdev, HCI_QUIRK_USE_BDADDR_PROPERTY);
+		hci_set_quirk(hdev, HCI_QUIRK_USE_BDADDR_NVMEM);
+		hci_set_quirk(hdev, HCI_QUIRK_BDADDR_NVMEM_BE);
+	}
 
 	kfree_skb(skb);
 

include/linux/blk_types.h

@@ -73,6 +73,9 @@ struct block_device {
 	int			bd_writers;
 #ifdef CONFIG_SECURITY
 	void			*bd_security;
+#endif
+#ifdef CONFIG_BLK_NVMEM
+	struct nvmem_device	*bd_nvmem;
 #endif
 	/*
 	 * keep this out-of-line as it's both big and not needed in the fast

include/linux/blkdev.h

@@ -30,6 +30,7 @@
 
 struct module;
 struct request_queue;
+struct nvmem_device;
 struct elevator_queue;
 struct blk_trace;
 struct request;

include/linux/of_net.h

@@ -15,6 +15,7 @@ struct net_device;
 extern int of_get_phy_mode(struct device_node *np, phy_interface_t *interface);
 extern int of_get_mac_address(struct device_node *np, u8 *mac);
 extern int of_get_mac_address_nvmem(struct device_node *np, u8 *mac);
+int of_get_nvmem_eui48(struct device_node *np, const char *cell_name, u8 *addr);
 int of_get_ethdev_address(struct device_node *np, struct net_device *dev);
 extern struct net_device *of_find_net_device_by_node(struct device_node *np);
 #else
@@ -34,6 +35,12 @@ static inline int of_get_mac_address_nvmem(struct device_node *np, u8 *mac)
 	return -ENODEV;
 }
 
+static inline int of_get_nvmem_eui48(struct device_node *np,
+				      const char *cell_name, u8 *addr)
+{
+	return -ENODEV;
+}
+
 static inline int of_get_ethdev_address(struct device_node *np, struct net_device *dev)
 {
 	return -ENODEV;